The present invention generally relates to object detection and, more particularly, relates to a vehicle object detection system and method of estimating the size of an object such as length and width dimensions.
Automotive vehicles are increasingly being equipped with collision avoidance and warning systems for predicting the potential collision with an external object, such as another vehicle or a pedestrian. Upon detecting a potential collision, such systems typically initiate an action to avoid the collision and/or provide a warning to the vehicle operator. Adaptive cruise control systems have been proposed to track a leading vehicle and automatically control the speed of the following vehicle. The ability to accurately predict an upcoming collision also enables a vehicle controller to control and deploy safety-related devices on the vehicle. For example, upon predicting an anticipated collision or near collision with an object, the vehicle seat belt pretensioner could be activated in a timely manner to pretension the seat belt, thereby enhancing the application of the safety device. The controller could also deploy a warning signal to notify the vehicle driver of a predicted collision with an object.
In conventional target tracking systems employed on automotive vehicles, the host vehicle is generally equipped with a sensor arrangement that acquires range, range rate, and azimuth angle (i.e., direction to target) measurements for each tracked target within a field of view. The sensor arrangement employed in many conventional collision detection systems is generally complex and costly and includes a plurality of radar beams or laser beams covering a field of view. In order to detect an anticipated vehicle collision with an object, the conventional collision detection system generally senses the presence of an object, tracks the movement of the sensed object, measures the azimuth angle of the object, range to the object, and range rate of the object, all relative to the host vehicle.
In addition to detecting the presence of an anticipated collision with an object it is also desirable to know the size of the object in order to determine whether or not to deploy one or more countermeasures and, if so, to further determine what type of countermeasures to deploy. For example, for an anticipated collision with a relatively large object, such as another vehicle or a pedestrian, it may be desirable to deploy certain countermeasures such as pretensioning the seat belt and deploying one or more air bags. However, for relatively small objects, such as a beverage container, no countermeasure deployment may be necessary. Further, it may be desirable to differentiate between certain types of objects, such as a pedestrian and a vehicle so as to deploy different countermeasures depending on the object size and/or type of object.
The above-mentioned prior known collision detection systems generally require relatively complex and expensive sensor arrangements which use multiple sensors that are required to measure the azimuth angle of the object, relative to the host vehicle, in addition to obtaining the range and range rate measurements. It is generally desirable to reduce the complexity and cost of systems and components employed in automotive vehicles.
It is therefore desirable to provide for a vehicle collision detection system which is able to estimate miss distance of an object and predict a potential collision with an approaching object that offers reduced complexity and cost. It is further desirable to provide for a cost affordable detection system and method of estimating the size of the object.
In accordance with the teachings of the present invention, a detection system and method of estimating a size dimension of an object are provided. According to one aspect of the present invention, the detection system includes a sensor for sensing an object within a field of view. The sensor measures range and range rate of the sensed object. The detection system further includes a controller for estimating a size dimension of the object as a function of the range and range rate. The controller estimates the size dimension absent an azimuth angle measurement of the object.
According to another aspect of the present invention, a method of estimating a size dimension of an object is provided. The method includes the steps of sensing the presence of an object, tracking the sensed object, measuring range to the object for each of a plurality of measurements, and determining range rate of the object for each of the plurality of measurements. The method also includes the steps of estimating a size dimension of the object as a function of the range and the range rate. The size dimension is estimated absent an azimuth angle measurement.
Accordingly, the detection system and method of estimating a size dimension of an object according to the present invention advantageously estimates a size dimension (e.g., length or width) of an object without requiring a complex and costly sensor arrangement, such as those which determine an azimuth angle measurement of the object.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.